Envin Scientific manufacture and supply optical filters to modify the characteristics of light as it either passes through or is reflected from a surface.
These filters work via reflection and/or absorption by layering special coatings on to a substrate and can provide complex and wide-ranging capabilities on a single or multiple optical filters.
In addition to the reflective properties or absorption profile of the coating itself, we can also introduce additional capabilities through the choice of substrate and the shape of the lens.
As a result, optical thin-film filters can function as windows or flat mirrors, lenses or curved mirrors, prisms and aspheric surfaces, adding mechanical function to the filter’s wavelength profile.
Some examples of optical thin-film filters manufactured by Envin Scientific include:
Each has a distinct profile of wavelengths and frequencies of light that can pass through or be reflected by the filter, while unwanted frequencies are absorbed to leave only the light that is needed for the given application.
These filters can have safety applications – for example by reducing glare from reflective surfaces – scientific uses by controlling the wavelength of a light source, and many other wide-ranging purposes besides.
All Envin Scientific optical thin-film filters are fully tested and qualified to recognised standards, so you can be confident that they provide the functionality you need.
We produce optical filters in the standard wavelength range from 175 nm to 8 microns using substrates up to 300 x 200 mm and from 0.1 mm to several centimetres thick.
Envin Scientific optical filters can be supplied unmounted, or if a mount is required, we can provide single filter holders, multiple filter wheels and matrix array assemblies.
We have several Perkin Elmer Lambda 900 spectrophotometers for testing in the range from 175 nm to 3.2 microns.
We also have a Perkin Elmer 983G which allows us to test in the range 2-30 microns for optical filters with a slightly longer wavelength profile.
All of our test results can be supplied in electronic format and are fully traceable back to specific process logs and machine runs.
Absorption filters work by absorbing specific wavelengths from the light that passes through them, to produce a more useful output spectrum.
There are several different materials that can be used for this, as well as several main types of absorption filter that can be created.
It is also possible to combine multiple filters by laminating or cementing them together, to create a single structure that delivers several different optical effects.
The main materials that can be used in spectral and absorption filters include glass, optical resin and dichroic filters.
Filters can produce a range of desirable effects:
Neutral density filters partially reduce the intensity of all wavelengths by the same amount, which in itself is an important capability that requires a high-quality absorption filter for reliable results.
Lamination allows the optical effects of multiple filters to be achieved in a single unit, and Envin Scientific can manufacture these in a variety of sizes and thicknesses.
Some of the structures that can be built include:
By combining different types of filter and laminating filters with different absorption spectra, more complex light output can be achieved than with a single filter used alone.
Envin Scientific can work with you to understand exactly what light profile you are trying to achieve, and can recommend suitable substrates, coatings, glass and resin filters to produce a laminated structure that achieves the specific wavelength bandpass required.
To find out more about all of the different types of optical filters Envin Scientific manufacture and supply, including both optical thin-film filters and absorption filters, please take a look around our website or get in touch with us.
You’ll find more specific details about each type of filter, from narrow bandpass, shortpass and longpass, through to neutral density filters and bespoke solutions for specific absorption spectra.
We can produce custom filters typically in thicknesses of 1, 2 or 3 mm and in sizes up to 50 x 50 mm, although we also manufacture a wide range of shapes and sizes down to as small as 1.4 x 1.4 mm.
The exact thickness of your filter may depend on its optical characteristics, as these can depend on the thickness of the material used in an absorption filter, and especially in laminated structures where multiple filters are layered together.